Have you cleaned out your cowl lately?

Cleaned my cowl with the air boxes and inner fenders off, so I could remove the rust. Sprayed Rust Destroyer from the inside holes and the engine cowl holes. I plan to do better w/ a foam brush thru the engine holes. I am consider the ideas posted about making cowl covers from magnetic sign material since otherwise leaves love to slide thru the long slots. Nobody ever opens the manual vent doors anyway since that blows leaves and dead rodents all over your clothes.